vault charm should tune open file parameter

[Patrizio Bassi]

We are hitting a bug with vault deploy charm: during startup, before unsealing, it consumes all the 1024 default open files (fds).

according to
https://developer.hashicorp.com/vault/tutorials/operations/performance-tuning a reasonable value should be much higher for that process (65536)

I implemented a workaround

juju exec --application=vault -- 'cat /proc/$(pidof vault)/limits | awk "NR==1; /Max open files/"'
juju exec --application=vault -- "sed -i 's/\[Service\]/\[Service\]\nLimitNOFILE=65536'/ /etc/systemd/system/vault.service"
juju exec --application=vault -- "systemctl daemon-reload"
juju exec --application=vault -- "systemctl restart vault"
juju exec --application=vault -- 'cat /proc/$(pidof vault)/limits | awk "NR==1; /Max open files/"'

juju exec --application=vault -- "systemctl status vault"
juju exec --application=vault -- 'export VAULT_ADDR=http://127.0.0.1:8200 && /snap/bin/vault status'

Can you apply in the charm or at least expose a parameter can be set via juju?

[James Page (james-page)]

Raising a task for the vault snap as well as newer versions can run the server daemon via the snap, rather than the charm provided systemd configuration.